The present invention relates to a modular building system and to individual modules or components that are useable therewith. Individual modules are at least substantially finished in a factory environment according to a predetermined design, after which they are transported to a proposed building site where they are set in place as a single module structure, or are coupled to other modules to yield a composite structure. A significantly short period of time is consumed at the building site due to the high degree of completion of the unit achieved at the factory.
Modular concepts of construction, in which individual building modules are pre-fabricated and moved to a building site, and second to additional modules to produce a desired structure are well established in the art. Similarly other known modular techniques involve remote prefabrication of components followed by component erection and completion of the structure at the building site. Generally speaking, however, both of the noted prior modular concepts have been fraught with problems and/or inherent limitations, such that the use of same has been severely limited. Specifically, while transport of the prefabricated module has precluded use of many conventional materials and has limited architectural design due to dimensional and structural considerations, prefabrication of components only, through less stringent in transport restrictions is both labor intensive and time consuming at the building site.
Exemplary of prior attempts at prefabrication of modules include the manufacture of rectangular-shaped modules which are limited in design and use by virtue of the necessity for supports internally of the modules. Such internal supports limit coupling of modules, restrict placement of internal walls within the module, or protrude into the intended useable interior where the supports must be enclosed, presenting aesthetically undesirable interior module features. In general, necessity for the internal supports has been dictated by lack of structural integrity of the system, per se, and in fact, one such system employs one or more temporary vertical supports during the manufacture of the module which remain in place until the modules are connected into a composite structure, at which time additional hidden supports are provided adequate to permit the removal of the temporary internal supports, whereby an unobstructed interior of at least a portion of the composite structure is achieved.
Other systems avoid the above noted problem by designing the module so that critical support elements are located around the exterior of the module. In these systems, though the interior of the modules may be unobstructed, the exterior becomes potentially aesthetically unappealing. Further, in both of the above described systems, the structural frames employed limit the modules to use in a totally cubic deployment.
Due to the lack of structural integrity of the individual prefabricated modules of the prior art, individual modules are generally assembled into a composite building with the aid of tensioning cables, tie rods, rigid support couplings, support beams that extend across joints between modules and the like. These various means that are utilized to strengthen the prior art modules are adequate to perhaps poorly unite adjacent modules into an overall structure, but are not adequate to overcome the patent lack of structural integrity of the modules per se which may be ascertained simply by movement about the interior of the structure. By way of example, one outstanding noticeable feature of normal modular construction is a lack of stability and rigidity of the floor. Normally floors in prefabricated, transportable structures exhibit resilience when one walks thereacross due to a lack of strength or rigidity that is exhibited by conventional flooring.
Prior attempts to overcome the noticeable floor effect of prefabricated construction have included fabrication of the floor from a reinforced concrete floor or conventional material at the building site, or the placement of structural reinforcement beneath the module at the building site, both of which detract from the efficiencies of the system, per se. In fact, prior to the present invention, there has been no modular construction that has employed a factory fabricated lightweight, reinforced concrete floor in the module which could be successfully transported from the factory to the building site without damage to the floor.
Prior art modular building systems involving fabrication of modules in a factory, followed by transport of the virtually completed module to a building site have followed two general structural techniques. One such technique includes exterior load bearing walls to achieve the degree of structural integrity and rigidity necessary for transportability of the module, and in fact, such modules generally include exterior load bearing walls of reinforced concrete, which is both architecturally and aesthetically limiting to the system. The second structural technique for such modular systems involves the inclusion of a load bearing structural framework to which non-load bearing exterior and interior walls are suitably affixed. Vertical load bearing columns are utilized in the framework, generally located at the four corners of the rectangular shaped module and at intermediate locations therebetween. The vertical columns may be secured between horizontal structural elements of the framework for the floor and roof of the module, or alternatively, the horizontal framework elements may be secured to the columns. Such structural framework arrangements of the prior art possess inherent disadvantages due to the requirement for intermediate supports between corner vertical supports, exposure of the vertical support columns around the exterior of the module, or the necessity to enclose the protruding vertical columns within the interior of the module.
All in all, reflecting on prior art modular construction systems, no system has existed heretofore in which basically conventional construction materials were utilized as would normally be found in an office, an industrial building, or a dwelling that was totally constructed on site. With the present invention, however, the modules, after virtually complete fabrication in the factory, are transportable to the building site without damage during transit. At the building site the modules are placed in the appropriate configuration according to the intended design for the structure, and adjacent modules are coupled to each other to ensure continuity of planar surfaces within the modules, such as the walls, floors, ceilings and the like, and generally without the necessity of additional structural coupling of the modules.
Insofar as the modular system according to the present invention is concerned, a number of important features are present that are totally devoid and unsuggested by the prior art. First, no internal supports are generally necessary other than at the corners of a basic support frame, whereby an endless series of modules could be coupled in side-by-side or end-to-end fashion to achieve any desired architectural arrangement compatible with conventional construction. In fact, if desired, modules according to the present invention may even be utilized in construction according to architectural designs other than the basic cubic or rectangular configuration. Cantilevered sections may be added to the basic support frame. Further, conventional materials are utilizable without damage during transit. Hence, once the modules are assembled at the building site and the finishing touches added, the overall structure from an exterior and an interior viewpoint is virtually undetectable as being modular in nature. Instead, though the houses constructed according to the present invention are modular in nature, once completed, the structure gives the appearance of a conventionally constructed building. In fact, as opposed to the norm for modular structures, maintenance and repairs to electrical or plumbing lines and conduits, and air handling ducts are easily achieved without destruction of a wall of the module.
Further, heretofore, modular structures that were intended for transport could not satisfactorily include monolithic concrete floors or gypsum type wall board panels, for during transport with the prior modular structures, damage would occur to both. According to the present invention, however, a monolithic reinforced concrete floor is employed that is capable of withstanding transit without even hairline fractures occurring in same, while in like fashion, gypsum wall panels may be utilized as interior wall surfaces without a danger of same becoming unsecured from the wall studs or fracturing as the result of induced stress during transit.
In general, while the prior art in the area of modular construction is quite voluminous, as exemplified below, none of the known prior art teaches or suggests the present invention. Exemplary of the prior art are the following listed patents. U.S. Pat. Nos. 3,225,434, 3,256,652, 3,289,382, 3,292,327, 3,377,755, 3,442,056, 3,470,660, 3,484,999, 3,550,334, 3,568,380, 3,738,069, 3,771,273, 3,940,890, 4,012,871, 4,023,315, 4,048,769, 4,065,905, 4,077,170, 4,125,981, 4,214,408, 4,219,978.